Zucchini Casserole with Ground Beef

This zucchini casserole with ground beef is a comforting, layered dish that swaps out the usual crust for a baked zucchini-and-cheese base. It’s packed with savory ground beef and tomato sauce in the middle and topped with melty cheddar cheese. This recipe comes together quickly and bakes in about 30–35 minutes, making it a perfect weeknight dinner that celebrates fresh zucchini while serving up hearty, family-friendly flavors.

This layered zucchini casserole with ground beef uses shredded zucchini to create a baked base mixed with cheese and eggs—no crust needed! The middle layer is a tasty ground beef and tomato mixture, all finished with a golden, melted cheddar topping. It’s an easy way to enjoy summer zucchini with a filling dose of protein and classic, homey flavors everyone will love.

This dish is great for busy weeknights since it only takes about 15 minutes of hands-on prep time followed by 30–35 minutes baking. It all comes together in one 13×9-inch pan, which means less mess. This recipe makes enough to feed 6 to 8 people, and it’s super flexible—you can swap in different sauces, cheeses, or protein to match what’s in your kitchen.

Keep reading for the full list of ingredients, clear step-by-step instructions, handy tips to prevent the base from getting soggy, plus some easy ways to switch up the recipe if you want it vegetarian, creamier, or with a bit of a kick.

Why You’ll Love This Dish

• The base is low-carb and gluten-free, built from shredded zucchini mixed with eggs and cheese instead of a pastry crust.
• It’s packed with protein thanks to the browned ground beef, making it a filling meal for busy families.
• Super versatile—you can swap tomato sauce for alfredo, change up cheeses, or switch proteins to suit your taste or pantry.
• Fast and fuss-free: it assembles quickly and bakes all in one pan for easy cleanup.

Ingredients You’ll Need

• Cooking spray
• 3 small to medium zucchini, shredded (about 4 cups or 1 lb 5 oz)
• 2 teaspoons salt (this helps draw out zucchini moisture)
• 4 large eggs
• 1 1/3 cups grated or shredded Parmesan cheese
• 3 cups shredded cheddar cheese (divided – some for the base, some for topping)
• 1 1/2 tablespoons oil
• 1 1/2 pounds ground beef
• 3/4 cup chopped onion
• 2 cups fresh mushrooms, sliced
• 1/2 cup chopped bell pepper (any color you like)
• 1 23-oz jar tomato, pasta, or spaghetti sauce (about 680 ml) — alfredo sauce works nicely too if you want a creamier version
• 1 1/2 tablespoons Italian seasoning (optional, but adds great flavor)

How to Assemble and Bake

1. Preheat oven to 400°F (200°C) and lightly spray a 13×9-inch pan with cooking spray.
2. Put shredded zucchini in a fine-mesh sieve, sprinkle with 2 teaspoons salt, toss, and let sit 15 minutes to draw out moisture.
3. Whisk 4 eggs in a medium bowl and stir in grated Parmesan and 3 cups shredded cheddar, reserving about 1 1/2 cups cheddar for the topping.
4. After zucchini rests, press it firmly with paper towels or a clean kitchen towel to squeeze out as much liquid as possible.
5. Add the squeezed zucchini to the egg-and-cheese mixture and stir to combine.
6. Spread the zucchini mixture evenly in the prepared pan.

7. Bake the zucchini base uncovered about 25 minutes, until it firms up and begins to turn golden.

   

8. While the base bakes, heat 1 1/2 tablespoons oil in a large skillet over medium heat.
9. Add chopped onion and sliced mushrooms to the skillet and cook 4–5 minutes until softened.
10. Add 1 1/2 pounds ground beef, break it up with a spoon, and cook until browned through.
11. Stir in 1/2 cup chopped bell pepper and cook 2–3 minutes; drain excess fat if needed.
12. Pour about a 23-oz jar of tomato (or preferred) sauce over the meat, add 1 1/2 tablespoons Italian seasoning if using, and simmer 2–4 minutes; remove from heat.
13. Spread the meat-and-sauce mixture evenly over the baked zucchini base.
14. Sprinkle the reserved cheddar cheese over the top.
15. Bake about 5 minutes more, until the cheese melts and bubbles.
16. Let the casserole rest about 10 minutes before cutting to allow it to set.

Pro Tips for Success

• Be sure to squeeze the zucchini very well—this step is key to keeping your casserole base from turning soggy. Press hard with towels to get out extra moisture.
• Don’t skip letting the casserole rest after baking for those 10 minutes. It helps everything hold together when you slice and serve.
• If your sauce feels watery, simmer it a bit longer before layering in the casserole to prevent sogginess.
• Put a rimmed baking sheet under your casserole dish while it bakes. It catches any messy spills and helps when pulling the pan from the oven.
• If you like a crispier base, bake the zucchini layer a few minutes longer on its own before adding the meat layer—just watch so it doesn’t burn.

Variations and Substitutions

• Swap up your protein choice: ground turkey, chicken, or Italian sausage are all delicious alternatives to ground beef.
• Make it vegetarian by skipping the meat and adding extra mushrooms, cooked lentils, or crumbled firm tofu with a little extra seasoning to keep it flavorful.
• Try different cheeses like mozzarella, Monterey Jack, or a smoked cheddar for a new twist. For creaminess, stir ricotta cheese into the zucchini base.
• Switch up sauces: marinara or arrabbiata for a spicy punch, or creamy alfredo sauce for a milder version.
• Want individual servings? Press the zucchini mixture into muffin tins, then top with the meat mixture and cheese for mini casseroles that are perfect for lunchboxes or parties.

How to Store and Reheat

• Refrigerate leftovers in an airtight container for up to 4 days. It tastes great cold or reheated.
• To freeze, cool your casserole completely, then wrap it tightly or pop it in a freezer-safe container. It will keep well for up to 3 months. Thaw overnight in the fridge before reheating.
• For reheating refrigerated portions, microwave for 1 to 3 minutes until warm, or bake at 350°F (175°C) for 15 to 20 minutes. From frozen, bake covered at 350°F (175°C) for 40 to 60 minutes until heated through.
• If you like to plan ahead, you can assemble the casserole (up through adding the meat layer) and refrigerate up to 24 hours before baking. Just add the cheese topping when you’re ready to cook.

Common Questions and Answers

• How many servings does this make? This casserole in a 13×9 pan typically serves 6 to 8 people, depending on portion size and appetites.
• Can I use frozen zucchini? Absolutely! Just thaw it completely and squeeze out as much water as possible before mixing it with eggs and cheese to keep the base firm.
• Can I leave out the eggs? Eggs help bind the zucchini base together. If you need an egg-free option, try a commercial egg replacer or mix 1 tablespoon ground flaxseed with 3 tablespoons water per egg, but note the texture might change slightly.
• What if my casserole comes out watery? Usually, not squeezing enough liquid from the zucchini or using a thin sauce causes that. Make sure to press out excess moisture well and thicken your sauce by simmering gently before layering.
• Can I make it spicy? Yes! Add red pepper flakes, a pinch of cayenne, or swap in a spicy sausage for some heat.